The primary thrust of this work will be to evaluate the role of bacterial surface components and salivary proteins in the adherence of the acidogenic streptococci and Actinomyces species to the tooth surface. Specific inhibition of adherence will be studied using each of the components obtained in a purified and characterized form. The specific aims of this work will be to: 1) Complete the purification and chemical characterization of the adherence binding component isolated from Streptococcus sanguis cell walls. 2) Isolate, purify and characterize binding components of Streptococcus mutans, Streptomitior, Actinomyces israelii, Actinomyces viscosus and Actinomyces naeslundii. 3) Utilize these radiolabeled bacteria and adherence binding components to determine the degree of relatedness of these binding components and to their site-specific interaction on saliva-coated hydroxyapatite. Additionally to study their specificity of binding utilizing purified salivary mucins. 4) Evaluate the potential role of immunoglobulins (primarily secretory IgA) on the aggregation of and the adherence to saliva-coated hydroxyapatite of these microorganisms. 5) Analyze the effectiveness of a variety of entities (compounds which may bind to these purified components based on their suspected chemical structure) which may inhibit the colonization of the individual microbe on the tooth by blocking specific reactive sites of the components involved in adherence. The ultimate goal of this study will be to uncover useful inhibitors of the basic adherence processes which lead to the formation of dental caries and periodontal disease.